As I understand it, you already have a #132. This of course has an isolated center-rail section to starve track power to the trolley...but does not use the insulated-outer-rail for triggering. If you don't want to mess with cutting/modifying the track section to install an insulated outer-rail, you can place a 10-cent magnet on the trolley(s) and then a 25-cent reed-switch in the track bed on the approach to the station. The reed-switch would then trigger the timer module to shut-off center-rail power via the relay for however many seconds.
OTOH, if you do use the insulated outer-rail method to trigger you may run into a so-called race condition which can create false/multiple triggers. See if this makes sense. The trolley arrives to the station section that has been modified with an insulated rail trigger. The trolley triggers the relay which stops the trolley. But the trolley is now sitting on the insulated rail. So when center-rail power is restored, the trolley instantly re-triggers the timer and maybe jerks for a fraction of a second and then stops again! Lather, rinse, repeat. So maybe you cut an insulated rail section that is only 1" long (or whatever) so that the trolley triggers the timer but rolls by the 1" trigger section under its own momentum before stopping. As you can see this technique is fraught with peril!
So to dig further down the rabbit-hole, what you could do in this situation is use 2 timers; you could have the insulated rail section the same length as the stop section. Both timers are triggered together but one is set to 10 second and the other is set to 15 seconds (or whatever). Power is removed from the center-rail for 10 seconds...but the outer-rail trigger section is disconnected from the timer triggers for 15 seconds. This gives the trolley 5 seconds to leave the station and roll out of the trigger section since the triggers have been disabled for 5 seconds when power is restored. Timer modules are only a few bucks so not really much of a penalty. The 2nd timer essentially duplicates the nichrome thermostatic switch delay in the 132 accessory. That is, when the trolley leaves the station it takes several seconds for the nichrome switch to cool down which gives time for the trolley to leave the station without instantly re-triggering the stop.
Separately, if you go with the insulated outer-rail trigger you probably want to use a wall-wart to supply the 12V DC power for the timer modules. The AC-to-DC converter module that Leo shows cannot be used as-is for most train transformer systems. That is, it creates a "new" DC- output voltage that does not play well with the AC common in most layouts. This has to do with the bridge-rectifier in the AC-to-DC voltage converter. We can get into the technical details of mixing AC and DC commons if interested, but a 12V DC wall-wart is only about $2-3 on eBay.
